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Thunderbolt and lightning, very, very frightening me
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The only thing better than pine trees might be cottonwood trees. That
is if you can stand all the fuzz they generate that gets into your air conditioner compressor! tim ab0wr On Wed, 9 May 2018 02:27:51 +0000 "Gordon Gibby" <ggibby@...> wrote: I understand that, it¡¯s just that my station has to run 24/7/365. |
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Jack Purdum
I remember a picture (QST I think) of the back of a house that was struck by lightning. The tower was on the left side and it looked like someone had taken black paint and painted perfectly straight lines all over the back of the house. What actually happened was the bolt super-heated the water in the plumbing, exploding the pipes under the pressure, taking the siding off the house like it was a chain saw. Scary.
Jack, W8TEE
On Tuesday, May 8, 2018, 11:30:15 PM EDT, Matthew Stevens <matthew@...> wrote:
Back in 2012 my next door neighbors maple tree was hit. It ran down the tree into the ground. To the north it ran along the galvanized water line where it blew the water meter and a chunk of the curbing across the street. To the south, it ran towards the house, jumped across the 8¡¯ wide concrete porch into the DOORBELL BUTTON.... blew a 4¡± hole in the concrete block wall, burnt all the interior house wiring (like, black scorched marks on the walls), shattering light bulbs and burning up light switches etc. burned the breaker panel out behind the house. It went from there into the phone line... to the pole in the street where it blew the cover off the 1940s era lead telephone junction box (found that down the street about 30yards). Went into my house via the phone line from that pole, tripped GFCIs in the back of the house, broke two light bulbs in the ceiling, and then through the cable line fried the cable modem-and literally scorched the on-board NIC off the motherboard on my fileserver which was connected directly to the modem/router. So yeah... I have a healthy respect for lightning :-) My radio in the front of the house was unplugged at the time - and fine. Not to say that a nearby strike can¡¯t cause issues even with an unplugged rig. But I think it¡¯s better than leaving it plugged in. At least it makes me feel better even if it¡¯s not accomplishing anything haha. 73, - Matthew nj4y On May 8, 2018, at 16:53, ajparent1/KB1GMX <kb1gmx@...> wrote:
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Steve Black
¿ªÔÆÌåÓýI had a 40 foot well grounded tower on my previous home. Right beside the tower was a shorter masonary chimney for a gas water heater. Lightning struck the chimney causing the top section to vaporize. The tower and radios that were connected to it had no damage. It made no sense to me at all. Several years earlier another strike hit the tower and vaporized the VHF/UHF?vertical and its coax right to the grounded entrance panel. Again no radios were damaged. That time the chimney was untouched. My electrician friend said having a tower was like making an obscene gesture at mother nature. Steve kb1chu Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: "Jack Purdum via Groups.Io" <jjpurdum@...> Date: 5/9/18 9:27 AM (GMT-05:00) Subject: Re: [BITX20] Thunderbolt and lightning, very, very frightening me I remember a picture (QST I think) of the back of a house that was struck by lightning. The tower was on the left side and it looked like someone had taken black paint and painted perfectly straight lines all over the back of the house. What actually happened was the bolt super-heated the water in the plumbing, exploding the pipes under the pressure, taking the siding off the house like it was a chain saw. Scary.
Jack, W8TEE
On Tuesday, May 8, 2018, 11:30:15 PM EDT, Matthew Stevens <matthew@...> wrote:
Back in 2012 my next door neighbors maple tree was hit. It ran down the tree into the ground. To the north it ran along the galvanized water line where it blew the water meter and a chunk of the curbing across the street. To the south, it ran towards the house, jumped across the 8¡¯ wide concrete porch into the DOORBELL BUTTON.... blew a 4¡± hole in the concrete block wall, burnt all the interior house wiring (like, black scorched marks on the walls), shattering light bulbs and burning up light switches etc. burned the breaker panel out behind the house. It went from there into the phone line... to the pole in the street where it blew the cover off the 1940s era lead telephone junction box (found that down the street about 30yards). Went into my house via the phone line from that pole, tripped GFCIs in the back of the house, broke two light bulbs in the ceiling, and then through the cable line fried the cable modem-and literally scorched the on-board NIC off the motherboard on my fileserver which was connected directly to the modem/router. So yeah... I have a healthy respect for lightning :-) My radio in the front of the house was unplugged at the time - and fine. Not to say that a nearby strike can¡¯t cause issues even with an unplugged rig. But I think it¡¯s better than leaving it plugged in. At least it makes me feel better even if it¡¯s not accomplishing anything haha. 73, - Matthew nj4y
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Thanks for this thought.
I drove 3 8' rods outside my shack, tied with #4, a block, a lightning arrestor (Alpha-Delta) and have not grid tied for exactly the reason you said and another.? I'm PME (TN-C-S) service and if there is a break in the upstream neutral/ground (tied in PME) then my shack ground could become the circuit ground for the neighborhood. I've considered running a very small gauge line from my shack ground to service ground for potential reasons and using it as a *fuse*, keeping it away from the house.? Any thoughts on that or other methods to avoid potential issues? |
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Concrete is apparently conductive enough.
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A really good ground can be had by tying into the rebar (steel reinforcement bars) embedded in a basement wall or the footing of a building or a concrete slab for a patio. Something to keep in mind if ever doing new construction. Maybe even worth digging a bit into the concrete of an existing structure, assuming you don't compromise it structurally or create a groundwater leak.? Jerry On Tue, May 8, 2018 at 12:18 pm, Gordon Gibby wrote:
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Hi Jerry, what you are describing is called a Ufer Ground.? Here in Olathe Kansas they are code.? Not sure but I believe it also requires all the rebar in the foundation to be tied together. 73, Bill? N0YUD Concrete is apparently conductive enough. A really good ground can be had by tying into the rebar (steel reinforcement bars) embedded in a basement wall or the footing of a building or a concrete slab for a patio. Something to keep in mind if ever doing new construction. Maybe even worth digging a bit into the concrete of an existing structure, assuming you don't compromise it structurally or create a groundwater leak.? Jerry |
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MAny years ago when I was a child, I remember lightening hitting the transformer across the street. The Primary electric line came loose, came into contact with the secondary to our home, bringing in the lightening and whatever else travels along the primary right to our circuit fuse (yes that long ago) box. I was in the basement at the time with my grandfather. That much current coming into the box blew it off the wall against the far fall a good 20 feet away! Meanwhile, my Mom and sisters were directly above, in the kitchen, doing dishes. They had just taken their hands out of the sink full of dishwater when all this went down. If they'd have waited a few more moments and... I don't like to think what would have happened next!
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James Lynes
At GT I took a couple of courses in Power Systems Engineering which turned out to be handy when I got into SCADA/EMS software. At any rate, in one of those classes, we calculated the forces involved in a 10,000 amp fault, an eye popping number. This became real when I saw the size of the bus bars in 12KV switch gear and the results of snakes and frogs getting into live front switches and transformers. |
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